The defender was one of three French-speaking players to sign on at the Stadium of Light in recent days, but he has expressed how important it is for him to speak the same language as his teammates.
"We must speak English first. It is important to talk to everyone. We all must speak the same language," he told the club's official website.
"When I played in Greece and Portugal, there were French players there, but everywhere I went I learned the language. Greek was very complicated."
The 26-year-old joined the Black Cats on a free transfer following his release from Maritimo.